diff --git a/equinox-fc/Domain/Allocation.fs b/equinox-fc/Domain/Allocation.fs
index 1fd7d485a..4bc4a5372 100644
--- a/equinox-fc/Domain/Allocation.fs
+++ b/equinox-fc/Domain/Allocation.fs
@@ -6,6 +6,9 @@ let streamName allocationId = FsCodec.StreamName.create Category (AllocationId.t
 // NOTE - these types and the union case names reflect the actual storage formats and hence need to be versioned with care
 module Events =
 
+    let [<Literal>] CategoryId = "Allocation"
+    let (|For|) id = FsCodec.StreamName.create CategoryId (AllocationId.toString id)
+
     type Commenced =    { ticketIds : TicketId[] }
     type Tickets =      { ticketIds : TicketId[] }
     type Allocated =    { ticketIds : TicketId[]; listId : TicketListId }
diff --git a/equinox-fc/Domain/Allocator.fs b/equinox-fc/Domain/Allocator.fs
index b83a3b4e5..01d778171 100644
--- a/equinox-fc/Domain/Allocator.fs
+++ b/equinox-fc/Domain/Allocator.fs
@@ -8,6 +8,9 @@ let streamName allocatorId = FsCodec.StreamName.create Category (AllocatorId.toS
 // NOTE - these types and the union case names reflect the actual storage formats and hence need to be versioned with care
 module Events =
 
+    let [<Literal>] CategoryId = "Allocator"
+    let (|For|) id = FsCodec.StreamName.create CategoryId (AllocatorId.toString id)
+
     type Commenced =    { allocationId : AllocationId; cutoff : DateTimeOffset }
     type Completed =    { allocationId : AllocationId; reason : Reason }
     and  [<Newtonsoft.Json.JsonConverter(typeof<FsCodec.NewtonsoftJson.TypeSafeEnumConverter>)>]
diff --git a/equinox-fc/Domain/Ticket.fs b/equinox-fc/Domain/Ticket.fs
index fdd00cc81..0f3a5a0fe 100644
--- a/equinox-fc/Domain/Ticket.fs
+++ b/equinox-fc/Domain/Ticket.fs
@@ -6,6 +6,9 @@ let streamName ticketId = FsCodec.StreamName.create Category (TicketId.toString
 // NOTE - these types and the union case names reflect the actual storage formats and hence need to be versioned with care
 module Events =
 
+    let [<Literal>] CategoryId = "Ticket"
+    let (|For|) id = FsCodec.StreamName.create CategoryId (TicketId.toString id)
+
     type Reserved =     { allocatorId : AllocatorId }
     type Allocated =    { allocatorId : AllocatorId; listId : TicketListId }
 
diff --git a/equinox-fc/Domain/TicketList.fs b/equinox-fc/Domain/TicketList.fs
index c452ac24e..167f4930f 100644
--- a/equinox-fc/Domain/TicketList.fs
+++ b/equinox-fc/Domain/TicketList.fs
@@ -6,6 +6,9 @@ let streamName listId = FsCodec.StreamName.create Category (TicketListId.toStrin
 // NOTE - these types and the union case names reflect the actual storage formats and hence need to be versioned with care
 module Events =
 
+    let [<Literal>] CategoryId = "TicketList"
+    let (|For|) id = FsCodec.StreamName.create CategoryId (TicketListId.toString id)
+
     type Allocated =    { allocatorId : AllocatorId; ticketIds : TicketId[] }
     type Snapshotted =  { ticketIds : TicketId[] }
     type Event =